Extrait du site de Robert Allan, chapire "Vocalion" :
One of the greatest French organ builders, Aristide Cavaillé-Coll, (b.1811) learned the art of reed voicing on harmonium reeds while in his teens. He was particularly influential on English builders in the mid 19th Century, especially Henry Willis who also began his career working with free reeds. Cavaillé-Coll did build early reed organs - the Poikilorgue is one built between 1833 and 1848. Much less well known are three 2MP monumental reed organs. One was in the Kaiser's hunting lodge in Louppy near Metz. A surviving working example is in the church of Ban de Sapt near Nancy . These were built in 1855 and may be a precursor of the Vocalion, not technically but in terms of important pressure reed organs built by a well-known pipe organ builder.
Despite its appearance with a spectacular array of false pipes above the console (hiding the swell shutters, action and wind chests), the instrument is actually a very large harmonium with 38 stops. The Grand division (lower manual) has 16 stops, some 4:6 ranks. The Recit (upper manual) has 14 stops, 4:4 ranks. Pedal division (3 ranks) and overall effects are controlled by 8 foot operated latches. It also has Barker lever action on the Grand, which is mentioned again near the end of this chapter. This instrument has been restored by German pipe organ company [which?] and is fully described in an article of HVN, the Dutch harmonium society .
 Willem van Buuren De Harmoniums van Cavaillé-Coll II Vox Humana, vol. 78, no. 2(HVN, April 2009) 6-10